Centrifugal pump



Dec. 15, 1970 R. J. WiLLETTE 3,547,554

' CENTRIFUGAL PUMP Filed April 7, 1969 3 Sheets-Sheet 1 Dec. 15, 1970 R. J. WILLETTE 3,547,554

CENTRIFUGAL PUMP Filed April 7, 1969 v 5 Sheets-Sheet 2 IN VENTOR. kussaz I W/LLIUZ' Dec. 15, 1970 w l T 3,57,54

CENTRIFUGAL PUMP Filed April '7, 1969 3 Sheets-Sheet 3 INVENTOR. USSELL J W/L L 77 United States Patent Oflice US. Cl. 415-213 13 Claims ABSTRACT OF THE DISCLOSURE An impeller for a centrifugal pump having a plurality of radially disposed fluid pressure creating passageways, with the leading edge of each of the trailing faces of the pressure passageways commencing at tangent points on the circumference of the inlet or intake opening, and with the outer portion of the trailing face of the pressure passageways being straight and extended radially outward. Each of the pressure passageways discharges into a pressure chamber and thence into an outlet or discharge passage which angles rearwardly from a radius line, relative to the direction of rotation of the impeller. The inlet port of the discharge passage is disposed forwardly in the direction of rotation of the impeller relative to the exit port of the discharge passage.

BACKGROUND OF THE INVENTION Field of the invention This invention relates generally to centrifugal pumps, and more particularly, to a novel and improved impeller for use in said pumps.

Description of the prior art Heretofore, many impellers for centrifugal pumps have been devised having curved vanes, as for example, United States Patent Nos. 1,065,731; 1,237,007; 1,721,692; 2,266,180; 2,291,760; 2,753,808; 2,791,183 and 3,228,344. However, the aforementioned patents disclose impellers having vanes which are shaped differently and which function differently than applicants impeller structure.

SUMMARY OF THE INVENTION This invention provides an impeller for centrifugal pumps which is adapted to be rotatably mounted in a pump casing on a horizontal axis and receive fluid from an axial inlet opening. The impeller comprises a solid rotor disc which has a plurality of paddles formed on the circumference thereof. A plurality of radially disposed fluid pressure creating passageways are formed in the rotor disc. Each of the pressure creating passageways includes a trailing or back face which has a convexly curved inner end portion, with the inner end of said inner portion commencing at a tangent point on the inlet opening and starting in a direction perpendicular to the radius of the inlet opening. Each of the pressure creating passageway trailing or back faces includes an outer end portion which is straight and radially disposed, and which commences at the outer end of said convexly curved inner end portion and communicates at its outer end with a discharge passage.

Each of the pressure creating passageways includes a leading or front face which has an inner end portion that is concavely shaped and circumferentially spaced apart from the back face convexly curved inner end portion. Each of the pressure creating passageway front faces includes an outer end portion which may be straight and disposed in a position so as to converge with the radial straight outer end portion of the back face, or which may be curved. The front face of each pressure creating passageway terminates at a point in the rotor disc spaced 3,547,554 Patented Dec. 15, 1970 from the back face, and it communicates with a discharge passage. The discharge passages angle rearwardly from a radius of the rotor disc, relative to the direction of rotation of the impeller. The discharge passages are preferably disposed at an angle in the range of from 20 to and including relative to a radius of the rotor disc. The paddles formed on the circumference of the rotor disc are disposed at the same angle as the discharge passages. In one embodiment, a circular fluid passageway is formed in the rotor disc in a position surrounding the pres sure creating passageways, and it has discharge openings communicating with the discharge passages. The rotor disc is preferably provided with two pressure creating passageways, although it may include three or four pressure creating passageways with corresponding discharge passages. In an embodiment having two pressure creating passageways, the impeller rotor disc is rotated in a direction so as to move the convexly shaped inner end portion of each of the back faces of the pressure creating passageways in a forward direction so as to create a pressure on the fluid in the inlet opening, perpendicular to the first part of said convex shape, and the rest of the convex shape will exert similar perpendicular forces over of the fluid in the inlet opening. The fluid is then forced over the convexly curved back face, against the concave front face and directed radially outward into a discharge passage and into the pump casing.

A disadvantage of some of the prior art centrifugal pumps is that the impeller vanes extend into the inlet opening. A further disadvantage of the prior art centrifugal pumps is that they do not provide pressure creating passageways having blades which are curved adjacent the inlet openings, and which curves commence at a tangent point on the circumference of the inlet opening and start in a direction perpendicular to the radius of the inlet opening. Accordingly, it is an important object of the present invention to provide an improved impeller for a centrifugal pump which overcomes the disadvantages of the prior art centrifugal pump impellers.

It is another object of the present invention to provide an improved impeller for centrifugal pumps which includes a plurality of fluid pressure creating passageways, each of which is provided with a back face having a convexly curved inner end portion commencing at a tangent point on the circumference of the inlet opening and starting in a direction perpendicular to the radius of the inlet opening, and an outer end portion which is straight and disposed on the radius line of the impeller so as to provide optimum conditions for increasing the velocity of fluid flow through the pressure creating passageways as the fluid is forced radially outward.

It is still another object of the present invention to provide a novel and improved impeller for a centrifugal pump which is simple and compact in construction, economical to manufacture, and efficient in operation.

Other objects, features and advantages of this invention will be apparent from the following detailed description, appended claims, and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of a centrifugal pump made in accordance with the principles of the present invention.

FIG. 2 is an end elevational view of the structure illustrated in FIG. 1, taken along the line 22 thereof, and looking in the direction of the arrows.

FIG. 3 is an elevational view of the impellar structure illustrated in FIG. 2, taken along the line of 33 thereof, and looking in the direction of the arrows.

FIG. 4 is a fragmentary, enlarged view of the discharge end of a pressure creating passageway and its discharge passage in the impeller structure of FIG. 3.

FIG. is a fragmentary, enlarged view of a modified discharge passage for use in the impeller structure of FIG. 3.

FIG. 6 is a fragmentary portion of a first modified impeller provided with three pressure creating passageways.

FIG. 7 is a fragmentary portion of a second modified impeller provided with four pressure creating passageways.

FIG. 8 is an elevational section view, similar to FIG. 3, of a third modified impeller, with the outer wall portion removed.

FIG. 9 is an elevational section view, similar to FIG. 8, of a fourth modified impeller.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, and in particular to FIGS. 1 and 2, an illustrative centrifugal pump is shown which comprises a casing or housing 10 having a base member 11. The casing 10 includes a delivery chamber 12 which is connected to a discharge nozzle or outlet pipe 13. As shown in FIGS. 1 and 2, the pump is provided with an impeller 14 which is made in accordance with the principles of the present invention, and which is rotatably mounted on a horizontal axis in the casing 10. The impeller 14 is mounted so that the top thereof extends above the lower wall 15 of the outlet pipe 13, for approximately a quarter of the way across the diameter of the pipe 13 to take advantage of the centrifugal force. The innermost point 16 of the bottom wall of the outlet pipe 13 is located as close as possible to the impeller 14 to scoop as much fluid from the impeller 14 as possible during rotating of the impeller. As shown in FIG. 2, the impeller 14 is rotatably mounted on one side by an integral drive shaft 17 which is rotatably mounted in suitable bearings 18 in the casing side wall 19. The other side of the rotor 14 is rotatably mounted by suitable bearings 20 which support the intake pipe 21 that is attached to the impeller 14. The intake pipe 21 would be connected to a suitable source of fluid. The inner end of the intake pipe 21 is provided with an intake or suction opening 22. The casing 10 may be made in any suitable manner to provide access to the interior of the casing to assemble the impeller in the casing.

As best seen in FIG. 3, the impeller 14 illustrates a first embodiment which includes a pair of fluid pressure creating passageways generally designated by the numerals 23 and 23a. Since each of these passageways is similarly constructed, only passageway 23 will be described in detail and marked with reference numerals, and the corresponding parts of the other passageway 23a will be marked with the same reference numerals followed by the small letter a.

The impeller 14 is made as a solid rotor disc from any suitable material. The pressure passageway 23 includes a trailing or back face that comprises an inner end portion 24 which is convexly curved or shaped and illustrated as being in the form of a semi-circle having a radius point marked by the numeral 25. The inner end of the curved face portion 24 commences at a tangent point 26 on the circumference of the inlet opening 22. The inner end of the curved face portion 24 starts out in a direction perpendicular to the radius of the inlet opening 22 or radius of the impeller 14. The outer end of the curved face portion 24 is shown at the point 28. The passageway back face further includes the outer straight radially disposed portion 27' which commences at the point 28 and extends radially outward to a discharge port 29.

As shown in FIG. 3, the pressure creating passageway 23 further includes a leading or front face, including a concave curved inner end portion 30 which is illustrated as being arcuate and drawn about the radius point 25. The concave curved face portion 30 commences at a tangent point 31 on the circumference of the inlet opening 22, at a point diametrically opposite to the commencing point 26 of the back face curved portion 24. The concave leading face inner portion is circumferentially spaced from the convexly curved inner end portion 24 of the back face of the pressure creating passageway 23. The front inner face portion 30 terminates radially outward at the point 32. The pressure creating passageway front face further includes the radial, outward extending portion 33 which commences at the point 32 and converges on the back face straight portion 27. The front face straight converging portion 33 terminates at the outlet port 29.

The curvature of the inner end portion 30 of the front face of the pressure creating passageway 23 is made parallel to the curvature of the inner end portion 24 of the back face surface. Both of the curved surfaces of the inher end face portions 24 and 30 are formed with a radius extended. from the point 25. It will be seen that the tangent point 26 is exerting a pressure directed to the center of the intake opening 22, and the tangent point 31 is also creating a similar pressure. The fluid passing through the inlet opening 22 into the two passageways 23 and 23a travels at the same velocity between the curved inner end portion faces, and when the fluid passes the point 32 it comes into contact with the straight radial back face 27 and the converging face 33 and the velocity of the fluid is increased. The center point 25 from which the curved inner end portion faces 24 and 30 are determined is disposed at a point radially outward from the tangent point 26 at a distance equal to the diameter of the inlet opening 22.

As shown in FIGS. 3 and 4, the pressure creating passageway 23 discharges through the port 29 into a conically shaped pressure forming chamber generally indicated by the numeral 34. The pressure chamber 34 is provided with the converging top and bottom walls 35 and 36, respectively. The pressure chamber 34 discharges the pressurized fluid through the inlet port 37 into the sloping discharge passage 38. The pressurized fluid in discharge passage 38 is discharged through an outlet or exit port 39 into the delivery chamber 12 in the pump casing 10.

As shown in FIG. 3, the impeller 14 is provided with a first semicircular passage 40 which coacts with a second semicircular passage 42 to surround the pressure passages 23 and 23a. One end of the passage 40 discharges through an outlet port 41 into the pressure chamber 34. One end of the passage 42 discharges through the outlet port 43 into the pressure chamber 34. The other ends of the passages 40 and 42 discharge through the outlet ports 41a and 43a, respectively, into the other pressure chamber 34a.

As shown in FIG. 2, the impeller 14 is provided around the periphery thereof with a pair of spaced apart peripheral flanges 44 and 45 between which are integrally formed a plurality of radially extended paddles 46. The paddles 46 are disposed at the same angle as the discharge passages 38 and 38a. The discharge passages 38 and 38a are disposed with the inlet port 37 circumferentially forward of the discharge port 39, relative to the direction of rotation of the impeller. It will thus be seen that the discharge passage 38 is disposed at an angle relative to the radial straight line outer end portion of the back face 27 of the pressure passageway 23. The discharge passage 33 is disposed at an angle of approximately 20 relative to the pressure passageway outer radial back face 27, in the clockwise direction or direction opposite to the direction of rotation, and with the outlet port 39 trailing the discharge inlet portion 37. It will be understood that the discharge passage 38 may be disposed at any angle in the range of from 20 to and through relative to the radial straight back face 27 of the passageway 23 and in the direction opposite to the direction of rotation.

The combined area of the outlet ports 29, 41 and 43 is formed approximately three times as large as the area of the inlet port 37 of the discharge passage 38 so that fluid pressure is always maintained at the inlet port 37.

FIG. illustrates the disposition of a discharge passage 38 at an angle of 90 relative to the pressure creating passageway back face portion 27.

In operation, the illustrative embodiment would be rotated in a counterclockwise direction, as viewed in FIGS. 1 and 3. The fluid entering through the inlet opening 22 would be engaged by the convexly curved surfaces 24 and 2411 of the inner end portions of the fluid passageways back faces, and forced outwardly into the respective pressure creating passageways 23 and 23a and then radially outward by centrifugal force into the discharge passages 38 and 38a, The fluid is then discharged under high pressure to the delivery chamber 12 from where it is forced out through the outlet pipe 13. As pressure is built up outside of the impeller 14, the fluid will fill the passageways 40 and 42 with fluid having the same pressure as the fluid discharging from the pressure creating passageways 23 and 2311 at the outlet ports 29 and 29a, respectively.

FIG. 6 illustrates a first modified impeller 14b made in accordance with the principles of the present invention and in which three fluid pressure creating passageways 23b, 23c, and 23d are provided. It will be seen that these three fluid pressure creating passageways are constructed in the same manner, and they function in the same manner, as the passageways 23 and 23a of the first impeller embodiment illustrated in FIG. 3.

FIG. 7 illustrates a second modified impeller 142 made in accordance with the principles of the present invention in which four fluid pressure creating passageways 23a, 231, 23g, and 2311 are provided. In this embodiment, the four fluid pressure creating passageways are constructed in the same manner, and they function in the same manner, as the passageways 23 and 23a of the first impeller embodiment illustrated in FIG. 3.

It will be understood that the fluid pressure creating passageways illustrated in the embodiments of FIGS. 6 and 7 would be provided with discharge passages made identical to the discharge passages of the embodiment of FIG. 3. The width of the inner end of each pressure creating passageway, between the curved face portions 24 and 30, will be determined by the number of passageways employed. The concave curvature of the front face of each pressure creating passageway is the same or is concentric with the curvature of the rear face. For a two-passageway embodiment, as shown in FIG. 3, the position of the center point 25 would be determined by the diameter of the inlet opening 22. The center point 25 is disposed at a point which is'radially outward from the adjacent tangent point 26, a distance equal to the diameter of the inlet opening 22. In other embodiments, where more than two pressure creating passageways are employed, the distance of the center point 25 radially outward from the adjacent tangent point is equal to the radius of the respective inlet opening. In the embodiments of FIGS. 6 and 7, the center points 25b through 25h are each disposed at a distance from their adjacent tangent point equal to the radius of the respective inlet opening.

FIG. 8 illustrates a third modified embodiment of the invention which employs a modified impeller indicated by the reference numeral 141. The parts of the impeller 141 which are the same as the corresponding parts of the impeller 14 of FIG. 3 have been marked with the same reference numerals followed by the small letter i. The impeller 141 is provided with two fluid pressure creating passageway 231. The same reference numerals have been used to indicate the parts of each of the passageways 231 since they are identical in construction.

Each of the fluid pressure creating passageways 231 includes a back face having a convexly shaped inner end portion 241 and a straight radially outward extended outer end portion 271. The curved inner end portion 241 is semicircular in shape and it is drawn from a radius point indicated by the numeral 251. The inner end of the curved back face portion 241' commences at a tangent point 261 on the circumference of the inlet opening 221. The inner end of the curved face portion 241 starts in a direction perpendicular to the radius of the inletopening 221.

Each of the preceding fluid pressure creating passageways 231 further includes a leading or front face that includes a concave curved inner end portion 301 and a continuing concave outer end portion 331. The concave curved inner end portion 301 commences at the tangent point 261 of the starting end of the inner face portion 241 of the other passageway 231. The latter face of each passageway discharges through a port 291 into a pressure forming chamber generally indicated by the numeral 341. The pressure forming chamber 341 discharges the pressurized fluid through the inlet port 371 of a sloping discharge passage 381. The pressurized fluid in the discharge passage 381 is discharged through an Outlet port 391 into the delivery chamber 12 in the pump casing 10.

The impeller 141 is provided with a pair of semicircular passageways 49 which are disposed radially outward from the inlet opening 221 and which surround the pressure passageways 231. Each of the pressure passageways 231 is enclosed at its outward end by a peripheral arcuate wall 47. The chamber wall 47 has an inwardly curved lip 48 at the forward end thereof which overlies the passageway discharge port 391. The trailing or rear end of the chamber wall 47 terminates at the inlet port 50 of one of the semicircular passageways 49. The outer end of the passageway back wall 271 also terminates at the last-mentioned inlet port 50. Each of the semicircular passages 49 is provided with an outlet port 51 that communicates with a pressure chamber 341. The numeral 52 generally indicates a radius line which is drawn from the center of the inlet opening 221 through the trailing side of the discharge nozzle inlet port 371. The arcuate distance between the radius line 52 and the rear face passageway radial face 271 is approximately 40. It has been found that if the trailing side of the discharge passage 381 is maintained in a range of from 40 preceding the passageway back wall 271 to that optimum high discharge pressures will be obtained at the discharge outlet port 391. The discharge passage 381 is disposed in the same angular relationship to the radius line 52 and the back radial wall 271 as was discussed hereinbefore for the embodiment of FIG. 3. The impeller 141 is provided with the same angularly disposed peripheral paddles 461 as is employed in the embodiment of FIG. 3. The impeller 141 illustrated in FIG. 8 functions in the same manner as the previously described embodiment.

FIG. 9 illustrates a fourth modified impeller 14j employed in the invention. The impeller 14 of FIG. 9 is constructed in the same manner as the impeller 141 of FIG. 8, with the exception that the discharge passage 38 has been moved forwardly in the direction of rotation, so that the trailing edge of the inlet port 371 is disposed at a point 140 preceding the radial back face 27 The parts of the embodiment of FIG. 9 which are the same as the parts of the embodiment of FIG. 8 have been marked with the same reference numerals followed by the small letter j.

It has been found that the best pressure range for the disposition of the discharge passages 381 and 38 is the range of from 40 to 140 preceding the pressure passageway back radial faces 271 and 271. It will be seen from an inspection of FIG. 9 that the inner end portion 30 of the passageway front face is convexly curved instead of being concavely curved. This convex shape is generated by continuing the convex inner end portion 24 of the other passageway and extending it around to form an approximate three-quarter circle which terminates at the point 53.

While it will be apparent that the preferred embodiments of the invention herein disclosed are well calcu lated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change.

What I claim is:

1. In a centrifugal pump, the combination comprising:

(a) a casing having a delivery chamber provided with an outlet pipe;

(1)) an impeller rotatably mounted in said casing in said chamber and having an axial fluid inlet opening;

(c) said impeller being constructed for rotation in one direction so as to receive fluid from said axial inlet opening and exert a centrifugal force on said fluid to pressurize the fluid and force it into the delivery chamber and thence out said outlet pipe;

(d) said impeller being provided with discharge passage means for discharging the pressurized fluid into the casing;

(e) said impeller being provided with a plurality of pressure creating passageways which each extend from the axial inlet opening radially outward into communication with said discharge passage means;

(f) each of said pressure creating passageways including a back face having a convexly shaped inner end portion commencing at a tangent point on the periphery of the axial inlet opening and starting in a direction perpendicular to the radius of the inlet opening, and a radially extended straight outer end portion; and,

(g) each of said pressure creating passageways further including a spaced apart front face that includes a concavely shaped portion.

2. A centrifugal pump as defined in claim 1, including:

(a) a plurality of radially outward extended paddles formed on the periphery of the impeller.

3. A centrifugal pump as defined in claim 1, wherein:

(a) a plurality of semicircular passageways surrounding said fluid pressure creating passageways, and each of said semicircular passageways having an outlet port communicating with one of said pressure creating passageways.

5. A centrifugal pump as defined in claim 3, wherein:

(a) each of said semi-circular passageways communicates with the outer end of a fluid pressure creating passageway.

6. A centrifugal pump as defined in claim 3, wherein:

(a) each of said discharge passages is disposed at an angle relative to the radially extended straight outer end portion of the back face of each pressure creating passageway.

7. A centrifugal pump as defined in claim 3, wherein:

(a) each of said discharge passages is disposed at an angle relative to the straight radial back face of the adjacent fluid pressure creating passageway, with its inlet port being disposed forwardly of its outlet po rt in the direction of rotation of the impeller.

8. A centrifugal pump as defined in claim 3, wherein:

(a) said front face of each fluid pressure creating passageway is provided with a concavely shaped inner end portion and a straight radial outer end portion which converges with the radially extended straight outer end portion of the back face.

9. A centrifugal pump as defined in claim 3, wherein:

(a) said front face of each fluid pressure creating passageway comprises a concavely shaped inner end portion and a continuous concavely shaped outer end portion.

10. A centrifugal pump as defined in claim 3, wherein:

(a) said front face of each of the fluid pressure creating passageways comprises a convexly shaped inner end portion and a concavely shaped outer end portion.

11. A centrifugal pump as defined in claim 3, wherein:

(a) each of said discharge passages is disposed with its inlet port at a position spaced forwardly about 40 from the straight radially extended outer end portion of the back face of the adjacent fluid pressure creating passageway in the direction of rotation.

12. A centrifugal pump as defined in claim 3, wherein:

(a) each of said discharge passages is disposed with its inlet port at a position spaced forwardly from the straight radially extended outer end portion of the back face of the adjacent fluid pressure creating passageway in the direction of rotation, and wherein said position is selected from a range of from 40 to and including 140 from said back face.

13. A centrifugal pump as defined in claim 3, wherein:

(a) each of said fluid pressure creating passageways includes a front face circumferentially spaced apart from said back face, and which passageway is enclosed at the periphery thereof by a concave peripheral face which has its leading end terminating at the discharge passageway for the fluid pressure creating passageway and its trailing end terminating at the inlet end of one of said semicircular passageways.

References Cited UNITED STATES PATENTS 619,7 6 2/1899 Edwards 1031 15 1,065,731 6/1913 Schneible 415211 1,237,007 8/1917 Wilstam 415204 1,721,692 7/1929 Carson 415-l88 2,266,180 12/1941 Emerick 416-186 2,291,760 8/1942 Rupp 41553 2,348,246 5/1944 Dixon 103115 2,753,808 7/1956 Kluge 416'183 2,791,183 5/1957 Ygge 416=184 3,228,344 1/1966 Cooper 416-477 FOREIGN PATENTS 115,070 4/19 18 Great Britain 416242 23,537 7/1913 Norway 415209 134,164 9/ 1929 Switzerland 416-243 55 HENRY F. RADUAZO, Primary Examiner US. Cl. X.R. 

